Most internal combustion engines rely on transmissions to provide optimal torque and vehicle speeds over a range of operating conditions. In contrast, electric vehicles, employing one or more electric motors, have a wide torque band capable of providing maximum torque output at low or high revolutions per minute (rpm). While some electric vehicles may include a multiple speed gearbox, the components of the transmission are generally designed to match the rpm of the electric motor to that of the drive wheels. Electric motors typically include an inverter configured to convert direct current (DC) electricity provided from a battery, or other DC power source, into alternating current (AC) electricity that may drive the electric motor and vehicle. The electric motor and inverter are part of the powertrain of an electric vehicle.
As the components of an electric drive system work by converting electrical energy into mechanical energy, and vice versa, the electric motor and inverter can generate significant heat. Adequately controlling the operating temperatures of the electric drive system is critical to maintaining the integrity and longevity of the electric motors and inverters. Today, vehicles employing two-motor systems typically have two completely different sets of cooling systems, including separate inverters (e.g., one inverter for each motor) and separate cooling systems for each motor/inverter in the vehicle.